Foster, C., Fitzgerald, D. J., & Spatz, P. (1999). Stability of the blood lactate-heart rate relationship in competitive athletes. Medicine and Science in Sports and Exercise, 31, 578-582.

The identification of heart rate (HR) and ratings of perceived exertion (RPE) associated with accumulations of 2.5 mM (aerobic threshold) and 4 mM (anaerobic threshold) of blood lactate, are commonly used to define training intensities. It is often assumed that HR at both thresholds changes with fitness alterations.

Speed skaters (M = 7; F = 6) were studied during the spring/off-season and fall/training-season using an incremental cycle ergometry protocol to study work, heart rate, and RPE at aerobic and anaerobic thresholds. The same factors were evaluated during maximal cycling-ergometer exercise (3000 m for females and 5000 m for males).

Power output at aerobic threshold, anaerobic threshold, and at maximal exercise increased with training. Neither HR nor RPE changed at any of the three exercise intensity levels because of training.

It was concluded that the stability of HR and RPE during training makes them practical markers of training intensity. Once those measures are determined for an athlete, they could be used as consistent indicators of training intensity.

Implication. Heart rates and ratings of perceived exertion do not change from no-training to trained states, despite changes in power output at various exercise intensities. Each could be used as a longitudinal indication of training intensity.

Return to Table of Contents for this issue.